The appearance of the great ray- xusnrli. cu .r5j4s-61xnn 0onsd2nge of brightness among stars is due to

  The absolute luminosity for most stars depenu:j3q) ji1mhc ds on the

  Four different main-sequence star(w jbfrbk*lrb:8/ hb/ s are colored blue, orange, red, and yellow. What is their rank from coolest to hlr/bbk r/wb8 b* fj:(hottest?

  A Hertzsprung-Russell diagram shows stars on h i mjt1+jqfnp/l+4f: a plot of

  A white dwarf star with a mass equal *)hz cmz,,znuto that of the Sun is about the size of

  The Chandrasekhar limit of stellb)igc( k yt;t gmg.ufvk1:83g ar mass (below which a star will collapse into a white dwarf) is, if the mass ot.i1f(:8gvgm bcgy) ktu ; gk3f our Sun is M, about

  Supernovas are thought to alw.;a6s -snt:jtet/dxh ays result in

  Black holes

  Pulsars are rapidly spinre*x+koad30 ls/ kdyj3v5 jfqzs3s,s0p. c9jning

State Einstein's principle of equivalenceuhq:szplw .o8h,nihsa5*-l 373mbuh .

  The Schwarzschild radius of a black hole is that radial distance from tl r-dnswyv;hp4842dkt4c;na he center of a sphere wivwdn;;nlh d4- k2y s8t4aprc 4thin which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einstein published his general relativity theory. It can be calculated from a star's mass M as: $R = 2GM/c^2$. Take the radius of both stars A and B as the Schwarzschild radius. If the mass of star A is twice as much as the mass of star B, the average density of star A, compared to star B will be

  When a distant source emila3ol+f1 l*l wts light of a particular wavelength in the visible, and the source is moving away from us, the c 1*l+lal fw3loolor of the light appears to us to be shifted toward the

  The cosmic background radiation corresprved- gm,l7: uonds to a temperature of about

  The Sun has apparent brightness at Eart n yumuizp7 .+/x4sgt0h ($1.5 \times 10^{8} \; km$ away) of B. What would be the apparent brightness of the Sun at Pluto, which is $6.0 \times 10^{9} \; km$ from the Sun?

  A star has absolute lhnv iry b()de*ej+w)k0+yf9vuminosity equal to that of the Sun ($1.5 \times 10^{8} \; km$ from the Earth) but is 10 pc away from the Earth. By what factor will it appear dimmer than the Sun?

  The Earth's orbit has a mean radius of jdzsy9o4y ) (d6wyam 0$1.5 \times 10^{8} \; km$. Over a six-month period, the apparent position of a particular star varies by $0.00014^{\circ}$ due to parallax. How distant is the star, in km?

  The Earth's orbit has a mea ;fjqc (2msd:g5gst9an radius of $1.5 \times 10^{8} \; km$. Over a six-month period, the apparent position of a particular star varies by $0.00014^{\circ}$ due to parallax. How distant is the star, in ly? (1 ly = $9.46 \times 10^{15} \; m$)

  What is the parallax angle for Proxima Cent m, xsu*1gl0wp4dk*kdauri, which is Earth's nearest star at 4.1 kdg,4*kmd*xlpwsu 0 3 ly?

  The apparent brightness of a stauehjsmjmfe)r- 2qs5h27 ob 24r is $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

  It can be shown that the approximate -j (q-zlypv)tf)wjl3bo +b)snc6k3 qage of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, 36)qb-)q+ )c-l j znfj3ospt ( ykwbvlin years.

  If a galaxy is moving away from us at 1.0% of the speed of light, how far awe cirjl3+f 2q3ay is it 3ef ql3jrci2+ from us?

  Estimate the speed of atj3 8c ;ksoqtnpgah8v,;s 5t2 galaxy that is 10 billion light-years away.

  Estimate the observed wavelength for the 656 nm line in the spectrum of a star wl5a3si.o9zpf/4y za9h rqx .ze; fb)nhich is 100 million light-ye9 z3za4 bof n x5;p/fe.q ysia9)h.zrlars from us.

  About 1 ms after the Big Bang,+a8 8 8ztlmvmv the temperature of the universe was about 1013 K. What energy (in eV) az v8+mtv88lmdoes this correspond to?